Latrodectus
Five species in the continental US: L. mactans (southern black widow), L. variolus (northern black widow), L. hesperus (western black widow), L. geometricus (brown widow, introduced), and L. bishopi (red widow, Florida endemic).
Loxosceles
Multiple species native to the south-central US, with L. reclusa (brown recluse) being the dominant clinical concern. Other species (L. deserta, L. arizonica) occur in southwestern deserts but cause few documented cases.
References
- [1]Medically Important Spiders - CDC NIOSH Workplace Safety. Accessed June 2026.
Related in Data
- Spider bite statistics (United States)Aggregated public-health data on verified spider bites in the United States, drawn from the American Association of Poison Control Centers National Poison Data System (NPDS)..
- Spider species richness by stateDocumented species counts per US state aggregate from state extension publications and museum records.
- Verified Loxosceles range (United States)Established populations of native Loxosceles species in the United States, based on museum specimens and verified field collections compiled by Vetter and collaborators..
- Latrodectus species distribution (United States)Native Latrodectus species occupy distinct overlapping ranges across the United States: L.
- Seasonality of indoor spider encountersIndoor sightings of large synanthropic spiders peak in late summer and early autumn in most US regions, driven primarily by male search activity rather than population growth..
- Poison control call trends (United States)AAPCC NPDS data show a steady ~3,500–4,500 annual calls coded for spider exposure across the past decade, with the majority classified as minor and fatalities essentially absent in recent reporting years..